.main{
    width: 500px;
    height: auto;
    overflow: auto;
    text-align: center;
    margin: 0 auto;
}
/*滚动条的样式设置*/
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}
::-webkit-scrollbar-thumb {
    background: linear-gradient(45deg, black, transparent);
    border-radius: 5px;
}
/*右键选中内容区的样式*/
::selection{
    color:#fff;
    background: #FF00FF;
}